ROSEMONT, Ill. (AP) — Jim Delany, one of the most influential figures in college athletics for three decades, will step down as Big Ten commissioner when his contract expires in June 2020.

The 71-year-old has been commissioner since 1989 and established himself as one of the biggest movers and shakers in U.S. sports. He oversaw three expansions to increase Big Ten membership from 10 to 14 schools and conference revenues increased dramatically under his watch.

"It's been an amazing opportunity to serve and lead these preeminent institutions, presidents, administrators, coaches and students," Delany said Monday in a statement. "It is incredibly fulfilling to support the hundreds of thousands of young men and women who have been afforded an opportunity to obtain best-in-class educations as a result of the invaluable, one-of-a-kind lessons learned through the unique combination of athletic and classroom competition."

Big Ten commissioner Jim Delany announced he will retire when his contract expires on June 30, 2020.(Photo: Patrick Gorski, USA TODAY Sports)

Delany became the Big Ten's fifth commissioner when he succeeded Wayne Duke in 1989. He ambitiously built the conference profile, negotiating television deals that in 2018 produced an unprecedented distribution of $51 million for Michigan, one of the flagship members.

When Delany launched the Big Ten Network in partnership with Fox in 2006, the Big Ten became the first Power Five conference with a television network devoted solely to programming of league events. The network was the first in cable/satellite history to reach 30 million households within its first 30 days on the air.

Delany expanded the Big Ten's geographic footprint from the upper Midwest to the East Coast. Penn State began competition in the league in 1991. Nebraska joined in 2011 and Maryland and Rutgers in 2014. The addition of Nebraska led the Big Ten to split into divisions in football and play a conference championship game. The additions of Maryland and Rutgers led Delany to open a second conference office in New York.

The Big Ten has prided itself on its measures to assure athlete welfare, such as being a leader in concussion treatment protocol and guaranteeing scholarships for four years. But the conference was also seen as behind the times when Delany initially led the resistance to creating the College Football Playoff. Big Ten football teams also underperformed as the league's chief rival, the Southeastern Conference, strung together seven straight national championships from 2006-12.

Ohio State won the national title in 2014, but the school gave the Big Ten a black eye last year over coach Urban Meyer's handling of domestic assault allegations against one of his assistant coaches.

Delany will leave his post on June 30, 2020. The Big Ten Council of Presidents and Chancellors has started a search for a new commissioner led by Northwestern president Morton Schapiro and the executive committee. The Los Angeles-based executive search firm Korn Ferry will assist.

Mar 2, 2019; Bloomington, IN, USA; Michigan State Spartans head coach Tom Izzo smiles after a play during the first half of the game against the Indiana Hoosiers at Assembly Hall. Mandatory Credit: Marc Lebryk-USA TODAY Sports Marc Lebryk, Marc Lebryk-USA TODAY Sports

Mar 2, 2019; Bloomington, IN, USA;Michigan State Spartans forward Kenny Goins (25) look at a shot that was blocked by Indiana Hoosiers forward Juwan Morgan (13) during the second half of the game at Assembly Hall.The Indiana Hoosiers defeated the Michigan State Spartans at the last second 63 to 62. Mandatory Credit: Marc Lebryk-USA TODAY Sports Marc Lebryk, Marc Lebryk-USA TODAY Sports

Mar 2, 2019; Bloomington, IN, USA;Michigan State Spartans guard Cassius Winston (5) lays up a shot during the second half of the game at Assembly Hall.The Indiana Hoosiers defeated the Michigan State Spartans at the last second 63 to 62. Mandatory Credit: Marc Lebryk-USA TODAY Sports Marc Lebryk, Marc Lebryk-USA TODAY Sports